None.
The present invention relates to lighting louvers and more particularly to curvilinear louvers.
Most of those acquainted with lighting louvers are familiar with rectangular arrays of reflectors used in ceiling mount or suspended installations. Such mounts are very common, especially for use with flourescent lights. It is known to use parabolic reflectors in such louver construction for desired illumination characteristics. Calculation of the parabolic configurations is a relatively straightforward procedure due to the rectilinear configuration of the louver grid.
High efficiency circular flourescent tubes have recently been developed. However, the light source produced by a circular or other curvilinear light source is not compatible with rectilinear louvers. The origin of the light (light source) is a factor taken into consideration when the parabolic reflector surfaces are considered. A curvilinear light source thus suggests if not, demands, a similarly curved reflective louver.
Curvilinear louvers have been produced in the past for use in conjunction with similarly shaped or curved light sources. However, such louvers have been produced with inner and outer parabolic reflector surfaces and with flat baffles extending between the two curved reflector surfaces. Flat baffles are not efficient reflectors when compared with specifically designed parabolic configurations. What was once a rectangular opening or cell in a louver becomes somewhat of a trapezoidal configuration in curvilinear louvers. A long reflector surface is located on one side, a short reflector surface on the other, and baffles that are substantially radially oriented with respect to a center of curvature are spaced apart along the curved reflector. Such spacing results in unfavorable physical shielding angles.
The advent of high efficiency circular lamps has thus created the need for a similarly circular louver with at least an approximation of the physical and optical shielding angle characteristics as the linear luminaire light control systems.